Balloon catheters are used for various medical procedures. For example, it is known to insert a balloon catheter into a passageway for dilation of the passageway such as is used in interventional bronchoscopy for the treatment of lung cancer and oft times, the resultant airway obstruction(s) that occur. Accordingly, balloon catheters have been routinely used with various endoscopes and with flexible and rigid bronchoscopes for dilation, as a tamponade to stop bleeding, and as an interference fixation device to hold instruments in place and prevent the retropulsion of those instruments under backflow pressure.
It is also known to use balloon catheters for removing undesirable biological material in bodily cavities. For example, inflatable balloon catheters may be employed as interventional tools for the excision and removal of unwanted materials—such as endoluminal obstructions and tumors and endovascular occlusions—in various applications, such as the interventional medical specialties of pulmonology, cardiology, urology, gynecology, gastro-enterology, neurology, otolaryngology, and general surgery. An example of such a device is disclosed in European Patent Application No. EP 1 913 882 by Karakoca. This device employs a balloon catheter with a hardening surface, which can be inserted into bodily cavities. After the device is inserted, the balloon is inflated, and the balloon is moved back and forth within the cavity such that the hardening surface resects on the unwanted biological material. For example, by pulling out the balloon, debris can be removed.
U.S. Patent Application Publication No. 2010/0121270 by Gunday (the '270 application) entitled Resector Balloon System, which is incorporated herein by reference, provides numerous improvements over Karakoca and relates to a balloon catheter with a textured surface that is operated in a pulsing fashion to shave the target material with minimal trauma. The '270 application discloses that a balloon system “is able to provide physiologic feedback to determine intra-lumen diameters.” This is accomplished in one embodiment by the provision of “a sensor that determines the pressure of the fluid output to the balloon and a sensor that determines the flow of the fluid output to the balloon.” Finally, the '270 application discloses that “by employing multiple, independently inflatable bladders or sinuses . . . one is able to more selectively and precisely . . . measure . . . intra-lumen diameters.”
However, the '270 application teaches measuring intra-lumen diameters by means of measuring pressure and adjusting the pulsing of the balloon catheter for resecting accordingly. While this method is very effective for resecting target material with minimal trauma (e.g. pressure measurement coupled with the pulsing of the balloon catheter), it would be advantageous to utilize a balloon catheter to provide accurate rendering of the interior surface of the cavity. Accordingly, the pulsing of fluid into the balloon catheter as taught in the '270 application for resecting, along with the associated control system for controlling the pulsing of the pump, would not be needed for such an application.
Various imaging systems for visualizing internal structures are known, including, for example, Magnetic resonance imaging (MRI), nuclear magnetic resonance imaging (NMRI), or magnetic resonance tomography (MRT) and computed axial tomography (CAT) or sometimes shorten to computed tomography (CT) scan. While these methods can be very effective at visualizing internal structures, the cost associated with the purchase and use of these machines is relatively high.
In the field of orthopedics it is often difficult, if not impossible, to assess the spatial dynamics between articular surfaces; especially as the articular surfaces translate in opposition to one another throughout their ranges of motion. During arthroplasty procedures, in particular, it would be advantageous to understand the geometries of the articular surfaces as well as the spaces within the joint in the effort to perfect anatomic restoration and joint kinematics, in general.
It may also be advantageous to use an electrically conductive balloon catheter within the intramedullary canals of bones. The Orthopedic and Trauma science has long struggled to visualize and measure the inner surfaces of bones in real time. The inability to map bone anatomy has hindered surgeon's ability to appropriately size and implant arthroplasty implants (e.g.—Hip Replacement—Femoral and Acetabular Implants). It has also hindered surgeons ability to assess the displacement of fractures and to appropriately size and implant fracture management systems (e.g.—Tibial Rodding and Plating systems).
Intra-cavity mapping is also known, such as is disclosed in U.S. Pat. No. 7,654,997 (Makower et al.). However, while Makower et al. uses a catheter device, it requires the use of an external sensor (apart from the balloon) to map and provide a 3-dimensional view of the cavity. (See, Col. 40, I. 64—col. 41, I. 24; FIGS. 7D-7E). This is cumbersome, difficult to manipulate and not practical for relative small cavities (e.g., intravascular measurement).
U.S. Pat. No. 5,752,522 (Murphy) discloses an apparatus for determining cross-sectional dimensions of body lumens, such as the diameter of a blood vessel. (Abstract). However, while Murphy discloses a design that includes a catheter having conductor bands which vary in resistance with balloon circumference (col. 9, II. 13-15), Murphy is limited to disclosing “conductor bands.” This will not provide a 3-dimensional view of the interior of a cavity, but rather, will only provide a cross-sectional circumference of a cavity. (See, FIG. 7).
What is desired, therefore, is a cost effective and reliable system and method for measuring and rendering internal structures of a body. It is further desired to provide a system and method for visualizing and measuring internal structures of a body that will not necessarily resect material from the internal structures during the processing of measuring the structures.